In general, a vehicle has windshield wipers to sweep the windshield so that a driver can see clearly while driving under rain or snow conditions. Wipers can be driven by vacuum or electricity. In particular, electric windshield wipers used in today's vehicles for sufficiently responding to rainfall or snowfall utilize a motor as a power source, operated by a battery.
A windshield wiper system activated by sensing rainwater has been developed and is frequently used today. The wiper system is designed to place a rain sensor inside a wiping pattern of a windshield glass to detect the amount of rainfall. The moving speed of the wiper is thus automatically adjusted according to the amount of rainfall and helps a driver obtain a clear visual field.
However, there is a drawback in the conventional windshield wiper system activated by sensing rainwater in that a multifunction switch and the rain sensor are distantly placed such that a wiring harness connecting the multifunction switch and rain sensor is increased in weight and manufacturing costs are high.
There is another drawback in that the sensitivity of the rain sensor is adjusted by measuring the resistance value of both ends of an intermittent volume (INT volume) of the multifunction switch, thus the sensitivity of the rain sensor can be affected by a voltage change generated from various factors inside the vehicle.